Watu mia moja walifika.

A useful breakdown is:

• watu = people
• mia moja = one hundred
• walifika = they arrived

So the sentence is literally structured as:

• People one hundred they-arrived

Natural English is One hundred people arrived.

Because Swahili verbs agree with their subject.

Here, the subject is watu (people), which belongs to the plural human noun class, often called class 2. Verbs with that kind of subject take the subject marker wa-.

So:

• wa- = they / plural people
• -li- = past tense
• fika = arrive

That gives:

• wa-li-fika = they arrived

If the subject were singular, for example mtu (person), the verb would change:

• Mtu mmoja alifika = One person arrived

Here a- matches singular human subjects.

Walifika is in the simple past.

It breaks down like this:

• wa- = subject marker, they
• -li- = past tense marker
• fika = verb root, arrive

So walifika means they arrived.

Compare:

• wanafika = they are arriving / they arrive
• wamefika = they have arrived / they are here
• watafika = they will arrive

In Swahili, mia means hundred and moja means one. So mia moja is literally hundred one, but it means one hundred.

This is normal Swahili number structure.

Examples:

• mia moja = 100
• mia mbili = 200
• mia tatu = 300

So watu mia moja means one hundred people.

In Swahili, numbers usually come after the noun they describe.

So:

• watu mia moja = one hundred people
• vitabu viwili = two books
• siku tatu = three days

This is different from English, where the number usually comes first.

So although English says one hundred people, Swahili says people one hundred.

Watu is plural and means people.

The singular is mtu, meaning person.

So:

• mtu = person
• watu = people

Examples:

• Mtu mmoja alifika = One person arrived
• Watu mia moja walifika = One hundred people arrived

This singular/plural pair is very common and important in Swahili.

Swahili does not normally use articles like English a, an, and the.

So Watu mia moja walifika can mean:

• One hundred people arrived
• The one hundred people arrived

The exact meaning depends on context.

English forces you to choose whether to include an article, but Swahili usually does not.

Yes. Walifika by itself means They arrived.

Swahili often allows the subject noun to be left out if it is already clear, because the verb already contains subject information.

So:

• Walifika = They arrived
• Watu mia moja walifika = One hundred people arrived

Adding watu mia moja makes it clear exactly who arrived.

By default, it is understood as exactly 100 people.

If a speaker wants to show approximation, they usually add something to indicate that, for example:

• takriban watu mia moja = about one hundred people
• karibu watu mia moja = nearly/about one hundred people

So without such words, watu mia moja normally means a precise count.

The normal and most natural order here is:

• Watu mia moja walifika

That is:

• subject noun phrase + verb

You may sometimes hear other orders for emphasis in larger contexts, but for a basic neutral statement, this is the standard pattern.

So if you are learning, Watu mia moja walifika is the form to remember.

Fika is a very common verb meaning arrive, reach, or get to depending on context.

In this sentence, walifika clearly means they arrived.

You may also meet related forms such as:

• kufika = to arrive
• amefika = he/she has arrived
• tumefika = we have arrived

So this sentence is a good example of a very common and useful verb.